Science..(unit 1)!!

• Oscillatory motion


  The periodic motion of the oscillating body around its rest point, where the motion is repeated through equal intervals of time

  
• Oscillatory motion


  • The oscillating body moves on both sides around its rest position
  • The displacements of the oscillating body around its rest position are equal
  • The velocity of the oscillating body reaches its maximum value when it passes its rest position and decreases gradually when it goes far from it until it reaches zero at the maximum displacement on both sides of rest position

  
• The oscillating body moves around its rest position, where the motion is repeated through equal intervals of time which is known as "Oscillatory motion"

  
• Velocity of an oscillating body

  Kinetic energy of the oscillating body is directly proportional to the mass and the squared velocity

  
• Periodic motion


  A motion which is regularly repeated in equal periods of time
• Amplitude


  The maximum displacement done by the oscillating body away from its rest position

  
• Complete oscillation


  The motion of an oscillating body when it passes by a fixed point on its path two successive times in the same direction

  
• Periodic time (T)


  The time taken for one complete oscillation

  
• Frequency


  The number of complete oscillations per unit of time

  
• Frequency


  Inversely proportional to the periodic time

  
• Frequency is the reciprocal of the periodic time

  
• Wave


  The disturbance that propagates and transfers energy in the direction of propagation
• Wave motion


  1. Vibration of medium particles at a certain moment and in a definite direction

  2. Direction of progression of the wave (line of wave propagation)
• Types of waves


  • Transverse waves
  • Longitudinal waves
• Transverse waves


  • Medium particles vibrate perpendicular to the direction of wave propagation
  • Formed from crests and troughs
• Longitudinal waves


  • Medium particles vibrate along the direction of wave propagation
  • Formed from compressions and rarefactions
• Transverse wave crest


  Equivalent to center of compression in longitudinal wave
• Transverse wave trough


  Equivalent to center of rarefaction in longitudinal wave
• Wave types


  • Electromagnetic waves
  • Mechanical waves
• Electromagnetic waves


  • Do not need a medium to propagate
  • All are transverse waves (e.g. light, infrared, radio)
• Mechanical waves


  • Need a medium to propagate
  • Include longitudinal waves like sound
• Lightning and thunder


  Lightning is electromagnetic, travels faster than sound (mechanical)
• Solar explosions


  We can see light (electromagnetic) but not hear sound (mechanical) from the sun
• Wavelength (λ)


  • Distance between two successive crests/troughs (transverse)
  • Distance between centers of two successive compressions/rarefactions (longitudinal)
• Wave amplitude


  Maximum displacement of medium particles from rest position
• Wave velocity (V)


  • Distance covered by wave per second
  • Constant in same medium, changes between media
• Wave frequency (F)


  Number of complete waves produced per second
• Law of wave propagation

  Wave velocity (V) = Wavelength (λ) x Frequency (F)
• Frequency (F) and Wavelength (λ)

  Inversely proportional in same medium
• Wave velocity (V) and Frequency (F)

  Directly proportional at constant wavelength
• Wave velocity (V) and Wavelength (λ)

  Directly proportional at constant frequency